1. Field of the Invention
The present invention relates to a lower thread winding device and a lower thread winding amount control device, and more particularly to a lower thread winding device suitable for supplying a lower thread to a bobbin without removing the bobbin from a horizontal holder.
2. Description of the Related Art
Conventionally, there have been proposed various lower thread winding devices capable of supplying a lower thread to a bobbin without removing the bobbin from a horizontal holder.
These conventional examples have been described in JP-A-11-47480. This publication has described that a needle bar is separated from an upper shaft by means of a needle bar separating mechanism and is held in an upper position during a thread winding operation, and at the same time, an outer holder and a bobbin are rotated through a lower shaft by means of a sewing machine motor and a thread is wound upon the bobbin, thereby carrying out lower thread winding.
[Problems that the Invention is to Solve]
In the conventional lower thread winding device, however, the needle bar separating mechanism is operated to disconnect the upper shaft from the needle bar, thereby stopping the needle bar in the upper position while the thread is wound upon the bobbin.
For this reason, even if the needle bar separating mechanism is operated to stop the needle bar, a thread take-up interlocking with the upper shaft does not stop but continues a vertical motion. For example, consequently, an upper thread is intermittently pulled and loosened by the thread take-up moving vertically while the thread pulled out of the supplied thread is wound by the lower thread winding device. In the case in which a sewing operation is automatically restarted after the lower thread winding operation is ended, therefore, a stitch formed immediately after the start of stitch formation is loosened.
Moreover, in the case in which a thread to be wound as a lower thread by the lower thread winding device is set to be an upper thread subjected to upper thread winding and the upper thread is pulled out and is wound upon the bobbin through a needle, a thread tension is changed by the thread take-up moving vertically. Therefore, there is a problem in that a great load is applied to each member of a thread winding mechanism through which the upper thread passes and thread fastening for the lower thread to be wound upon the bobbin fluctuates.
In some cases in which the upper thread acts violently and is thus entangled with a component on a thread path or slips out of the needle by the vertical motion of the thread take-up during the thread winding operation or the upper thread is to be wound upon the bobbin, moreover, the thread is pulled so that the upper thread cannot be appropriately guided to a winding position. Furthermore, the needle bar separating mechanism is incorporated around the needle bar. Therefore, there is also a problem in that a structure is complicated in the vicinity of the needle bar.
The invention has been made in consideration of these respects and has an object to stop a needle bar and a thread take-up while a lower thread is supplied to a bobbin without removing the bobbin from a horizontal holder by a lower thread winding device.
In order to achieve the object, a first aspect of the invention is directed to a lower thread winding device comprising:
a bobbin including upper and lower flanges provided on a central shaft upon which a lower thread is to be wound and both ends thereof, the upper flange having a slit opened to an outer peripheral edge;
a horizontal holder having an inner holder capable of accommodating the bobbin and an outer holder provided with a blade tip for catching a thread;
a bobbin driving member provided on an axial center of the outer holder and capable of being rotated integrally with the outer holder;
first moving means for moving the bobbin driving member to a connecting position in which the bobbin driving member and the bobbin are connected to cause the bobbin to be rotatable during an operation for winding the thread upon the bobbin and a separating position in which the bobbin driving member is disconnected from the bobbin during a sewing operation;
a thread holding member including a thread holding portion capable of holding a thread end of the thread supplied to the bobbin during the thread winding operation and a thread position regulating portion for positioning the supplied thread on a supply side by the thread holding portion during the thread winding operation to abut on the upper flange, the thread holding portion being movable to a retreat position in the vicinity of an outer peripheral surface of the outer holder and an entry position in which the supplied thread is caused to enter an inner upper part of the inner holder to be positioned above the upper flange during the thread winding operation;
second moving means for moving the thread holding portion of the thread holding member to the retreat position and the entry position;
an upper shaft clutch mechanism (410, a needle oscillation stepping motor 446) provided between a drive shaft (a lower shaft 414) to be driven by a sewing machine motor and a reciprocating member (a thread take-up crank 456) for reciprocating a needle bar and a thread take-up in a vertical direction and capable of carrying out electrical switching into a connecting state in which the drive shaft is connected to the reciprocating member during the sewing operation and a holding state in which the connection is released and the thread take-up and the needle bar can be held in an upper position during a lower thread winding operation; and
thread winding operation control means (193, 193A) for operating the first moving means and the second moving means to cause a supplied thread connected between the thread holding portion and the thread position regulating portion to enter the slit and for bringing the upper shaft clutch mechanism into a release state so that the thread can be wound upon the bobbin without vertically moving the thread take-up and the needle bar during the thread winding operation. By employing such a structure, it is possible to easily supply the bobbin with the thread to be used for embroidering without removing the bobbin from the horizontal holder. In addition, since the thread take-up is not moved vertically during the thread winding operation, the thread does not act violently and the upper thread can be prevented from being entangled or cut.
Moreover, a second aspect of the invention is directed to a lower thread winding device comprising:
a bobbin including upper and lower flanges provided on a central shaft upon which a lower thread is to be wound and both ends thereof, the upper flange having a slit opened to an outer peripheral edge;
a horizontal holder having an inner holder capable of accommodating the bobbin and an outer holder provided with a blade tip for catching a thread;
a bobbin driving member provided on an axial center of the outer holder and capable of being rotated integrally with the outer holder;
first moving means for moving the bobbin driving member to a connecting position in which the bobbin driving member and the bobbin are connected to cause the bobbin to be rotatable during an operation for winding the thread upon the bobbin and a separating position in which the bobbin driving member is disconnected from the bobbin during a sewing operation;
a thread holding member including a thread engaging portion capable of holding a thread end of an upper thread supplied to a needle during the thread winding operation and a thread position regulating portion for positioning the upper thread on a supply side by the thread engaging portion during the thread winding operation to abut on the upper flange, the thread engaging portion being movable to a retreat position in the vicinity of an outer peripheral surface of the outer holder and an entry position in which the supplied thread is caused to enter an inner upper part of the inner holder to be positioned above the upper flange during the thread winding operation;
second moving means for moving the thread engaging portion of the thread holding member to the retreat position and the entry position;
an upper shaft clutch mechanism (410, the needle oscillation stepping motor 446) provided between a drive shaft (the lower shaft 414) to be driven by a sewing machine motor and a reciprocating member (the thread take-up crank 456) for reciprocating a needle bar and a thread take-up in a vertical direction and capable of carrying out electrical switching into a connecting state in which the drive shaft is connected to the reciprocating member during the sewing operation and a holding state in which the connection is released and the thread take-up and the needle bar can be held in an upper position during a lower thread winding operation; and
thread winding operation control means (193, 193B) for bringing the upper shaft clutch mechanism into the connecting state to drive a sewing machine, thereby catching the upper thread connected to the needle by means of the blade tip of the outer holder and separately rotating the upper thread in upper and lower parts of the inner holder, then causing the thread engaging portion of the thread holding member to catch the upper thread passing over the inner holder, and thereafter operating the first moving means and the second moving means to cause the supplied thread connected between the thread engaging portion and the thread position regulating portion to enter the slit and bringing the upper shaft clutch mechanism into a release state so that the thread can be wound upon the bobbin without vertically moving the thread take-up and the needle bar during the thread winding operation. By employing such a structure, it is possible to easily supply the bobbin with the upper thread to be the lower thread without removing the bobbin from the horizontal holder. In addition, since the thread take-up is not moved vertically during the thread winding operation, the thread does not act violently and the upper thread can be prevented from being entangled or cut.
Furthermore, a third aspect of the invention is directed to a lower thread winding device comprising:
a bobbin including upper and lower flanges provided on a central shaft upon which a lower thread is to be wound and both ends thereof, the upper flange having a slit opened to an outer peripheral edge;
a horizontal holder having an inner holder capable of accommodating the bobbin and an outer holder provided with a blade tip for catching a thread;
a bobbin driving member provided on an axial center of the outer holder and capable of being rotated integrally with the outer holder;
first moving means for moving the bobbin driving member to a connecting position in which the bobbin driving member and the bobbin are connected to cause the bobbin to be rotatable during an operation for winding the thread upon the bobbin and a separating position in which the bobbin driving member is disconnected from the bobbin during a sewing operation;
a thread catching and holding member including a thread holding portion provided in a tip portion and serving to hold a thread supplied during the thread winding operation and a thread engaging portion for engaging an upper thread, and a thread position regulating portion provided on a rear end side from the thread holding portion and the thread engaging portion and serving to position a supplied thread on a supply side by the thread holding portion and the thread engaging portion or the upper thread supplied as a lower thread during the thread winding operation to abut on the upper flange of the bobbin, in which a tip portion is always placed in a retreat position in the vicinity of an outer peripheral surface of the outer holder and is placed in an entry position in which the tip portion enters an inner upper part of the inner holder during the thread winding operation;
second moving means for moving the thread holding portion and the thread engaging portion in the thread catching and holding member to freely advance or retreat between two positions including the retreat position and the entry position;
an upper shaft clutch mechanism (410, the needle oscillation stepping motor 446) capable of carrying out electrical switching into a connecting state in which a drive shaft (the lower shaft 414) to be driven by a sewing machine motor is connected to a reciprocating member (the thread take-up crank 456) for reciprocating a needle bar and a thread take-up in a vertical direction during the sewing operation and a holding state in which the connection is released and the thread take-up and the needle bar can be held in an upper position during a lower thread winding operation;
a first thread winding operation control portion (193A) for operating the first moving means and the second moving means to cause the supplied thread connected between the thread holding portion and the thread position regulating portion to enter the slit and for bringing the upper shaft clutch mechanism into a release state so that the thread can be wound upon the bobbin without vertically moving the thread take-up and the needle bar during the thread winding operation; and
a second thread winding operation control portion (193B) for bringing the upper shaft clutch mechanism into the connecting state to drive a sewing machine during the thread winding operation, thereby catching the upper thread connected to a needle by means of the blade tip of the outer holder and separately rotating the upper thread in upper and lower parts of the inner holder, then causing the thread engaging portion and the thread position regulating portion in the thread catching and holding member to catch the upper thread passing over the inner holder, and thereafter operating the first moving means and the second moving means to cause the supplied thread connected between the thread holding portion and the thread position regulating portion to enter the slit and bringing the upper shaft clutch mechanism into a release state so that the thread can be wound upon the bobbin without vertically moving the thread take-up and the needle bar during the thread winding operation.
By employing such a structure, it is possible to easily supply the bobbin with the supplied thread to be used for embroidering or the upper thread to be the lower thread without removing the bobbin from the horizontal holder. In other words, it is possible to easily select the type of the lower thread to be supplied to the bobbin depending on a stitch. In addition, since the thread take-up is not moved vertically during the thread winding operation, the thread does not act violently and the upper thread can be prevented from being entangled or cut.
Moreover, a fourth aspect of the invention is directed to the lower thread winding device according to the first or third aspect of the invention, further comprising:
a thread separating portion (an inclined surface 47 for thread separation) protruded from the outer peripheral surface of the outer holder and capable of moving the supplied thread positioned in the vicinity of the outer peripheral surface of the outer holder in a separating direction from the outer holder when the outer holder is normally rotated; and
a reholding operation control portion (a lower thread reholding operation control portion 194) for setting the thread holding member or the thread catching and holding member into a thread catching position which is placed above the retreat position, then rotating the outer holder to move the supplied thread positioned in the vicinity of the outer peripheral surface of the outer holder in the separating direction from the outer holder, thereby operating the thread holding member or the thread holding portion (an upper thread holding portion 59) of the thread catching and holding member to hold the supplied thread after the thread winding operation is completed. By employing such a structure, it is possible to efficiently carry out the thread winding operation when using the supplied thread.
Furthermore, a fifth aspect of the invention is directed to the lower thread winding device according to the second or third aspect of the invention, further comprising an upper thread reeling mechanism (120) including thread loosening means (130) for releasing the upper thread supplied as the lower thread at time of start of the thread winding operation; and
an upper thread control portion (195) for causing an amount of reeling of the upper thread reeled from the upper thread reeling mechanism to be a set amount at time of the start of the thread winding operation and for operating the thread loosening means to release the upper thread when the bobbin winds the upper thread to be the low thread. By employing such a structure, it is possible to easily and reliably supply the bobbin with the upper thread to be the lower thread without removing the bobbin from the horizontal holder.
Moreover, a sixth aspect of the invention is directed to the lower thread winding device according to the first aspect of the invention, further comprising a thread catching hook (46) formed on the outer peripheral surface of the outer holder, an outer holder reverse rotating mechanism (205) for reversely rotating the outer holder, lower thread tension means (25) including a thread introducing port fixed to the inner holder and serving to introduce the lower thread to be the supplied thread to move along an upper surface of the inner holder when the outer holder is reversely rotated by means of the outer holder reverse rotating mechanism, and a lower thread tension applying portion (196) for setting the lower thread connected to the bobbin into the retreat position to be positioned below an upper surface of the outer peripheral surface of the outer holder and causing the thread catching hook to catch the lower thread connected to the bobbin, then reversely rotating the outer holder and operating the lower thread connected to the bobbin to enter the thread introducing port after the thread winding operation is completed. By employing such a structure, it is possible to easily apply a proper tension to the lower thread wound upon the bobbin after the thread winding operation is ended.
Furthermore, a seventh aspect of the invention is directed to the lower thread winding device according to the sixth aspect of the invention, further comprising a cutting blade fixed to the outer peripheral surface of the outer holder to be opposed to the blade tip in an almost tangential direction; and an opening portion formed on the outer peripheral surface of the outer holder at this side in a direction of rotation to be adjacent to the cutting blade when the outer holder is reversely rotated. By employing such a structure, it is possible to easily cut the lower thread wound upon the bobbin from the supply side after the thread winding operation is ended.
Moreover, an eighth aspect of the invention is directed to a lower thread winding device, further comprising thread winding amount setting means for setting an amount of winding of the lower thread to be wound upon the bobbin, thread winding diameter detecting means for detecting a maximum thread winding diameter of the lower thread to be wound upon the bobbin, thread winding number measuring means for detecting a thread winding rotation number during the thread winding operation of the bobbin, and a thread winding amount control portion for carrying out the thread winding operation until the thread winding diameter detecting means detects the maximum thread winding diameter of the lower thread wound upon the bobbin if the thread winding amount of the lower thread is set to have a maximum set value by the thread winding amount setting means, and carrying out the thread winding operation until the thread winding number measuring means detects the thread winding rotation number of the bobbin which is stored and set depending on the thread winding amount set by the thread winding amount setting means if the thread winding amount set by the thread winding amount setting means is less than the maximum set value. By employing such a structure, it is possible to reliably supply the bobbin with the lower thread in a proper amount.
Furthermore, a ninth aspect of the invention is directed to the lower thread winding device according to the first or third aspect of the invention, further comprising thread hold detecting means for detecting that the thread supplied during the thread winding operation is held in the thread holding member or the thread catching and holding member. By employing such a structure, it is possible to easily detect the suitability of the start of the thread winding operation using the supplied thread.
Moreover, a tenth aspect of the invention is directed to the lower thread winding device according to the first, second or third aspect of the invention, further comprising a sewing data storage portion for storing a plurality of pattern sewing data, pattern selecting means for selecting desirable pattern sewing data from the pattern sewing data, and an automatic setting portion for automatically setting selection of the lower thread to be supplied to the bobbin depending on the pattern sewing data selected by the pattern selecting means and/or a thread winding amount of the lower thread. By employing such a structure, it is possible to automatically set the selection of the lower thread and the thread winding amount of the lower thread depending on the pattern sewing data. Consequently, it is possible to easily carry out the operation.